World's Shortest Highway Tunnel
Shady Valley, Tennessee
Backbone Rock is 75 feet high but only a few feet wide. In 1901 the Tennessee Lumber Company wanted to get its lumber trains from the woods to the nearest town by the shortest route, so they simply blasted a big hole through the rock. The rail bed eventually became a lumber road and then Tennessee Highway 133, which now passes through Backbone Rock Tunnel, still the shortest in the world. The little notch at the top of the tunnel-hole was reportedly chiseled by hand after it was found that train smokestacks were just a little too tall to pass through.
The Lumber Company packed up and left over a hundred years ago. The trees have all grown back and the area around Backbone Rock now has picnic tables and an official Forest Service sign, which features a little hand-drawn lumber train chugging through the tunnel.
In the 1930s, during the Great Depression, trails were built and uneven steps were hand-cut into the Backbone Rock on both sides of the highway, leading to the top -- the closest thing we've seen to the Stairs of Cirith Ungol from The Lord of the Rings.
The adventurous can make the climb to the top and walk across the highway from above -- but please be aware of slippery leaves, a lack of handrails, and a 75-foot-drop if you make a mistake. We were content to admire the tunnel from the ground.